RNSTO:mine ends with K00161 . and about the 7850 c50 and c24 ,works fine with me.
RNSTO...mine would have worked fine too. After all, there is no physical contact between the spokes and the chainstay. I opted not to use it because of a recommendation by a Cervelo customer service rep. He indicated that if for some reason during a ride the wheel goes out of true (i.e. a broken spoke), chances are very high that you may have physical interference with the chainstay.